Portfolio Thumbnails modified to open an image

<?php
/*

Template Name: Portfolio with Filter

 */
global $data;
?>
<?php get_header(); ?>

        <section class="page-title">
            <div class="double-separator"></div>
            <div class="breadcrumbs">
                <div class="one-fourth align-left">
                    <?php if (function_exists('dt_breadcrumbs')) dt_breadcrumbs(); ?>
                </div>

                <div class="three-fourth column-last align-right">
                    <ul id="filters">
                        <li><?php _e('Sort By: ', 'haze'); ?></li>
                        <li class="selected active"><a data-value="all" href="#"><?php _e('All', 'haze') ?></a></li>
                        <?php
                            $terms = get_terms('portfolio_cats');
                            $count = count($terms);
                            $i=0;
                            $term_list = '';
                            if ($count > 0) {
                                foreach ($terms as $term) {
                                    $i++;
                                    $term_list .= '<li class=""><a href="#" data-value="'. $term->slug .'" class="'. $term->slug .'">' . $term->name . '</a></li>';
                                    if ($count != $i)
                                    {
                                        $term_list .= '';
                                    }
                                    else
                                    {
                                        $term_list .= '';
                                    }
                                }
                                echo $term_list;
                            }
                        ?>
                    </ul>
                </div>
            </div><!--end breadcrumbs-->
            <div class="double-separator"></div>
        </section>
    </div><!--end top-->

    <div class="centered-wrapper">

        <section id="portfolio-wrapper">

        <?php if ( post_password_required() ) echo get_the_password_form(); else { ?>

            <ul class="portfolio <?php if($data['portfolio_cols']) echo strtolower($data['portfolio_cols']); ?>-columns">

                <?php
                //get post type - portfolio
                query_posts(array(
                    'post_type'=>'portfolio',
                    'posts_per_page' => -1,
                    'paged'=>$paged
                ));

                // Begin The Loop
                if (have_posts()) : while (have_posts()) : the_post();

                // Get The Taxonomy 'Filter' Categories
                $terms = get_the_terms( get_the_ID(), 'portfolio_cats' );

                //Apply a data-id for unique indentity,
                //and loop through the taxonomy and assign the terms to the portfolio item
                // which will be referenced to Quicksand
                ?>
                <li data-id="id-<?php echo $count; ?>" class="<?php if($terms) { foreach ($terms as $term) { echo $term->slug .' '; } } else { echo 'none'; } ?>">

                    <?php
                        // Check if wordpress supports featured images, and if so output the thumbnail
                    if ( (function_exists('has_post_thumbnail')) && (has_post_thumbnail()) ) :

                        $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'portfolio-single' );

                        // Output the featured image ?>
                        <a rel="prettyPhoto[pp_gal]" href="<?php echo $image[0]; ?>"><?php the_post_thumbnail('portfolio-thumb'); ?></a>

                    <?php endif; ?>

                    <?php // Output the title of each portfolio item ?>
                    <h4><a href="<?php the_permalink(); ?>"><?php echo get_the_title(); ?></a></h4>
                    <?php the_excerpt(); ?>
                    <div class="count hidden"></div>
                </li>

                <?php $count++; // Increase the count by 1 ?>
                <?php endwhile; endif; // END the Wordpress Loop ?>
                <?php wp_reset_query(); // Reset the Query Loop ?>
            </ul>
            <?php } ?>
        </section>

    </div><!--end centered-wrapper-->

<?php get_footer(); ?>